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Differential pair to multiple paths

vicvicvarunis

Hi all,

I'm trying to keep a differential pair but my design needs to split the paths at some point and return to the original. Below is an example I found but can't make it work. I have PCB Editor Pro with Pspice

Thanks

  • excellon1

    Hi

    The GND net looks to be incorrect, usually GND would be considered a plane to reference a signal against.

    Typically a diff pair means a balanced connection of 2 nets of a certain impedance between a source & load, for example a USB connection or something similar.

    In your design what 2 nets make up the actual Diff Pair ?

  • vicvicvarunis
    in reply to excellon1

    Hi  thanks for the observation. This is an unusual setup indeed but we need it to be routed in a similar fashion as I showed in the picture. For the moment ignore the GND net 

    One trace of the diffpair (the N trace) needs to go through the two pin connection (Termination terminal) and then return back to the its matching pair (P trace). Below the picture

    The signals are not highspeed but we are treating them as diffpairs.  Is there a way we can do this? Thanks 

  • excellon1
    in reply to vicvicvarunis

    Hi Vic.

    In the picture is the 2 pin connection just a Shunt so you have a method to Enable/Disable a termination resistor for the diff-pair.. ?

    It kind of looks that way ..

    By any chance is what you are calling a diff-pair really getting used for I2C or Spi digital instead ? Anyway there is really not enough info to make a good assesment
    because the actual topology of the circuit is unknown so it is just a guessing game.

    Do you have a use case for exactly you are trying to do ?. Maybe post a pic of what you have, not some other design and perhaps i can help you out.

    Thanks .

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